Reactive Magnetron Co-sputtering Method Research Articles

Palladium enhanced electrochemical supercapacitive performance of chromium oxide thin films synthesized by sputtering process

Recently, the use of transition metal oxide electrodes for supercapacitor applications has increased due to the possibility of variable mixed valence states. The present study has established the use of Pd-Cr2O3 composite thin films as a working electrode for high-performance supercapacitors. The reactive dc magnetron co-sputtering method has been used for the fabrication of thin film of Cr2O3 and Pd-Cr2O3 on SS-304 substrate. X-ray diffraction and X-ray photoemission spectroscopy techniques were used to examine the surface chemistry and phase purity of chromium oxide and Pd-Cr2O3 composite thin films. The incorporation of Pd in Cr2O3 delivers a drastic change in the surface morphology. Due to the modified morphology and electronic properties, a noticeable improvement in the electrochemical properties of Pd-Cr2O3 electrode is observed. The obtained value of specific capacitance for this electrode is 401 Fg−1 at 0.1 mAcm−2 scan rate and within the potential window range 0 to +1.2 V. This value of specific capacitance is almost twice in comparison to the Cr2O3 based electrode. The Pd-Cr2O3 composite thin film shows a good cycle retention capability of 8000 cycles with 87.5 % retention. The obtained value of energy density and power density for Pd-Cr2O3 electrode was 80.2 Whkg−1 and 3.23 kWkg−1, respectively at 0.1 mAcm−2. Consequently, this composite material electrode can be seen as a promising advancement for electrodes in supercapacitor devices.

Reset-First and Multibit-Level Resistive-Switching Behavior of Lanthanum Nickel Oxide (LaNiO3-x) Thin Films.

The resistive random-access memory (RRAM) with multi-level storage capability has been considered one of the most promising emerging devices to mimic synaptic behavior and accelerate analog computations. In this study, we investigated the reset-first bipolar resistive switching (RS) and multi-level characteristics of a LaNiO3-x thin film deposited using a reactive magnetron co-sputtering method. Polycrystalline phases of LaNiO3 (LNO), without La2O3 and NiO phases, were observed at similar fractions of Ni and La at a constant partial pressure of oxygen. The relative chemical proportions of Ni3+ and Ni2+ ions in LaNiO3-x indicated that it was an oxygen-deficient LaNiO3-x thin film, exhibiting RS behavior, compared to LNO without Ni2+ ions. The TiN/LaNiO3-x/Pt devices exhibited gradual resistance changes under various DC/AC voltage sweeps and consecutive pulse modes. The nonlinearity values of the conductance, measured via constant-pulse programming, were 0.15 for potentiation and 0.35 for depression, indicating the potential of the as-fabricated devices as analog computing devices. The LaNiO3-x-based device could reach multi-level states without an electroforming step and is a promising candidate for state-of-the-art RS memory and synaptic devices for neuromorphic computing.

Structural, Optical, and Dielectric Properties of Ion-Conducting LiAlO2 Thin Films Produced by Reactive Magnetron Co-sputtering

This study reports on the properties of LiAlO2 thin films compared to Al2O3 and Li2O thin films, considering their application as an ion-conducting dielectric in metal–insulator–metal (MIM) capacitors. The reactive magnetron co-sputtering method for the deposition of LiAlO2 is presented for the first time. This room-temperature method dedicates an amorphous LiAlO2 film with a smooth surface (Rrms ∼ 0.34 nm) and uniform morphology, which was determined by X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) techniques. UV–vis spectroscopy points to the formation of LiAlO2 with high transparency and a wide band gap. The fabricated MIM capacitors were analyzed using impedance spectroscopy to determine the cross-plane conductivity and dielectric properties. Incorporation of lithium ions into the alumina results in an ionic conduction mechanism with a room-temperature conductivity of 2.23 × 10–11 S cm–1 and activation energy of 0.69 eV consistent with the Arrhenius relation. The capacitance–frequency study for LiAlO2-based capacitors shows a stabilized behavior with a capacitance of 123.51 nF/cm2. The enhancement in the dielectric constant (k ∼ 25.76) coupled with a high band gap energy (Eg ∼ 5.49 eV) is determined. These results suggest the production of thin film capacitors with better energy storage performance and lower loss by using an ion-conducting dielectric.

High-entropy alloy nitride nanofilms via a co-sputtering method enable superior optical performance and thermal robustness

• HEN (ZrNbMo-Al-N) films are prepared through a reactive magnetron co-sputtering method. • A tri-layer SSA is fabricated based on HEN (ZrNbMo-Al-N) films. • The absorbers on Cu substrates show high absorptance (96.2%) and low emittance (6.6%). • The absorbers on SS Substrates exhibit superior thermal robustness at 400 °C. High-entropy ceramics are a new class of solar-thermal material with high configurational entropy, lattice distortion, and flexible component space. In this work, we report a tri-layer solar selective absorber based on high-entropy nitride (ZrNbMo-Al-N), which can be deposited on various substrates through reactive magnetron co-sputtering. The absorbers on Cu substrates exhibit a remarkable solar absorptivity of 96.2% and a suppressed thermal emissivity of 6.6%. Moreover, the absorbers on stainless steel (SS) substrates show superior thermal robustness. After annealing at 400 °C for 168 h in a vacuum condition, they retain a high absorptivity of 94.4% and a low thermal emissivity of 9.8%.

Effect of Zr content on the structure and morphology of CrZrN thin films prepared by reactive DC magnetron co-sputtering method

In this research, nanostructured chromium zirconium nitride (CrZrN) thin film has been deposited on Si(100) substrates by reactive DC magnetron co-sputtering method without in situ substrate heating and post-deposition annealing. The effects of Zr content on thin film structure and morphology were investigated. The Zr content in the films were varied by applied the sputtering current of Zr target (Izr) in the range of 300 to 900 mA, whereas the current of Cr target was kept at 300 mA. The crystal structure, microstructure, morphology, thickness, and chemical composition were characterized by glancing angle X-ray diffraction (GA-XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) techniques, respectively. The results showed that the increase of Izr not only increased the deposition rate, but also increased the Zr content of the as-deposited film ranging from 3.9 to 26.5 at%. The as-deposited thin films were formed as a (Cr,Zr)N solid solution, with fcc structure in (111) and (200) plane, where Cr atoms were replaced by Zr atoms in the CrN lattice. The 2θ diffraction peaks were shifted to the lower value as increase of Zr content which was obtained by increased Izr. The nanocrystalline CrZrN structure with crystal sizes smaller than 10 nm structure were calculated for as-deposited thin films. The lattice parameters increased from 4.187 to 4.381 Å, whereas the crystal size decreased from 8.3 to 6.4 nm. The FE-SEM images of all the CrZrN films exhibited compact columnar with dense morphology as a function of Zr content. Moreover, the thickness of the CrZrN thin films was increased of 302 – 421 nm.

Microstructure, mechanical properties and corrosion behavior of Ce doped TiN films

The Ce doped TiN (Ti-Ce-N) films with different Ce contents (1.91, 5.75, 7.95, 9.16, 14.19 at.%) were prepared by reactive magnetron co-sputtering method using Ti and Ce target as the Ti and Ce supplier, respectively. Microstructural observation results indicate that the Ti-Ce-N films with Ce contents from 1.91 to 9.16 at.% exhibit a single face centered cubic structure and the film with Ce content of 14.19 at.% transforms into an amorphous structure. The substitution of Ce atoms for Ti atoms in Ti-Ce-N films leads to the increase of cell volume and grain refinement. Measurement results of mechanical properties show that the hardness and elastic modulus of Ti-Ce-N films are increased as the increase of Ce content from 1.91 to 9.16 at.% because of solution strengthening and fine-grained strengthening. Polarization curves and electrochemical impedance spectroscopy indicate that the corrosion resistances of TiN films are improved obviously with Ce doping contents of 9.16 at.% and 14.19 at.% compared with undoped TiN film.

Metal-semiconductor transition at a comparable resistivity level and positive magnetoresistance in Mn3Mn1−xPdxN thin films

Thin films of antiperovskite Mn3Mn1−xPdxN with x up to 0.36 were grown by reactive magnetron co-sputtering method. All the deposits exhibit a [1 0 0] preferential orientation, with the lattice constant slightly enlarged in samples with ever more Pd atoms partially substituting the MnI atoms in Mn3MnN matrix. The replacement of MnI atoms in antiperovskite structure by Pd atoms, besides reducing the saturation magnetization, also invokes a metal-semiconductor transition which occurs remarkably at a comparable resistivity level. Moreover, a positive magnetoresistance was observed in samples of a high Pd content. These tunable electrical and magnetic properties of ternary antiperovskite compounds might promise some ingenious applications in electronic industry.

DEPOSITION AND CHARACTERIZATION OF MAGNETRON CO-SPUTTERED InAlN FILM AT DIFFERENT Ar:N2 GAS FLOW RATIOS

This work presents the influence of changing Ar:N2 gas ratio on the growth and properties of InAlN films. InAlN films were deposited on [Formula: see text]-type Si(111) substrates by using magnetron co-sputtering method in 6:12, 10:10, 12:8 and 12:6 Ar:N2 mixtures at 300[Formula: see text]C. The surface, structural, electrical and optical properties of the deposited films were evaluated at different Ar:N2 ratios. The grain size and film thickness were increased by increasing the Ar flow with respect to N2. Structural characterization by X-ray diffraction (XRD) revealed an improvement in the crystalline quality of the [Formula: see text]-axis-oriented InAlN film by adjusting the Ar:N2 ratio to 12:8, however no diffraction peak corresponding to InAlN was detected at 6:12 Ar:N2 mixture. The surface roughness of InAlN film exhibited an increasing trend whereas the electrical resistivity of the film was decreased by increasing the Ar:N2 ratio. The bandgap of InAlN film was calculated from the optical reflectance spectra and it was found to change by changing the Ar:N2 gas ratio. The analysis of results from this work shows that the InAlN film with improved physical properties can be obtained through reactive magnetron co-sputtering method by adjusting the Ar:N2mixture to 12:8.

Structural and emission properties of Tb3+-doped nitrogen-rich silicon oxynitride films

Terbium doped silicon oxynitride host matrix is suitable for various applications such as light emitters compatible with CMOS technology or frequency converter systems for photovoltaic cells. In this study, amorphous Tb3+ ion doped nitrogen-rich silicon oxynitride (NRSON) thin films were fabricated using a reactive magnetron co-sputtering method, with various N2 flows and annealing conditions, in order to study their structural and emission properties. Rutherford backscattering (RBS) measurements and refractive index values confirmed the silicon oxynitride nature of the films. An electron microscopy analysis conducted for different annealing temperatures (TA) was also performed up to 1200 °C. Transmission electron microscopy (TEM) images revealed two different sublayers. The top layer showed porosities coming from a degassing of oxygen during deposition and annealing, while in the region close to the substrate, a multilayer-like structure of SiO2 and Si3N4 phases appeared, involving a spinodal decomposition. Upon a 1200 °C annealing treatment, a significant density of Tb clusters was detected, indicating a higher thermal threshold of rare earth (RE) clusterization in comparison to the silicon oxide matrix. With an opposite variation of the N2 flow during the deposition, the nitrogen excess parameter (Nex) estimated by RBS measurements was introduced to investigate the Fourier transform infrared (FTIR) spectrum behavior and emission properties. Different vibration modes of the Si–N and Si–O bonds have been carefully identified from the FTIR spectra characterizing such host matrices, especially the ‘out-of-phase’ stretching vibration mode of the Si–O bond. The highest Tb3+ photoluminescence (PL) intensity was obtained by optimizing the N incorporation and the annealing conditions. In addition, according to these conditions, the integrated PL intensity variation confirmed that the silicon nitride-based host matrix had a higher thermal threshold of rare earth clusterization than its silicon oxide counterpart. Analysis of time-resolved PL intensity versus TA showed the impact of Tb clustering on decay times, in agreement with the TEM observations. Finally, PL and PL excitation (PLE) experiments and comparison of the related spectra between undoped and Tb-doped samples were carried out to investigate the impact of the band tails on the excitation mechanism of Tb3+ ions.

Structure and Properties of Zrtio4 Thin Films Prepared by Reactive Magnetron Co-Sputtering Without Heating

ZrTiO4 thin films were deposited by reactive dc magnetron co-sputtering method without heating. The crystal structure, surface morphology, thickness, optical and dielectric properties of the thin films were investigated. At sputtering currents above 2.0 A without heating ZrTiO4 thin film was crystallization of the orthorhombic phase (111). The values of refractive index were ranged between 2.01 and 2.23 (at 650 nm). The optical packing density values were ranged between 0.85 and 0.96. From this study, it was observed that the refractive index values were strongly dependent on packing densities. The high dielectric constant width decreases from 74.3 to 43.3 when sputtering current increases, which is higher than other research.

Microstructure and piezoelectric properties of reactively sputtered highly C-axis ScxAl1-xN thin films on diamond-like carbon/Si substrate

We report deposition of pure AlN and ScxAl1-xN thin films with different Sc concentration on DLC/Si substrate by RF and DC reactive magnetron co-sputtering method by using Al and Sc as targets. The X-ray diffraction (XRD) results showed that the films have high c-axis-orientation. Electron probe microanalyzer (EPMA) analysis reveals the presence of scandium atoms reduce the space occupied by aluminum atoms, leading to lattice distortion during the phase transition. The SEM cross-section results showed that the ScxAl1-xN films are highly aligned along c-axis and have columnar like morphology. The top view of SEM results indicated that the new phase formation above Sc 30.33%, however no new peak appeared in the XRD pattern. The piezoelectric coefficient (d33) of ScxAl1-xN thin films are measured and the highest value (11.54 pC/N) is achieved at x=30.33% increasing 14 times, as that with AlN/DLC/Si, 0.73 pC/N. ScxAl1-xN films on DLC/Si substrate have a great potential to be applied on high frequency SAW devices in the future.

Effect of Al content, substrate temperature and nitrogen flow on the reactive magnetron co-sputtered nanostructure in TiAlN thin films intended for use as barrier material in DRAMs

TiAlN thin films were deposited by using the reactive magnetron co-sputtering method whit individual Ti and Al targets, where the Ti and the Al targets were simultaneously powered by using DC and RF sources, respectively. the electrical resistivity and the structural and microstructural properties of the deposited TiAlN thin films and the effects of Al content, substrate temperature and nitrogen gas flow rate on those properties were investigated. At a low flow rate of nitrogen gas (0.51 sccm), the electrical resistivity of the films was found to increase with increasing AC power, but at a high flow rate of nitrogen gas, it was found to decrease. The structural and microstructural analyses performed by using X-ray diffraction and scanning electron microscopy (SEM) showed that with increasing substrate temperature from room temperature to 400 ℃, the films prepared at 400 ℃ have a crystalline structure while those prepared at room temperature had an amorphous nature. Also, the SEM analysis revealed that with decreasing AC power and increasing nitrogen flow rate, the size of the grains in the prepared films become larger.

Bactericidal efficiency of nanostructured Al–O/Ti–O composite thin films prepared by dual magnetron reactive co-sputtering technique

Mixed oxide Al–O/Ti–O composite nanostructured thin films were prepared at Ar:O2 gas ratio of 70:30 (7:3 in sccm) by reactive magnetron co-sputtering method. The effect of Al in the films on the antibacterial efficiency has been studied. In situ optical emission spectra (OES) were recorded in order to study the plasma chemistry as well as nucleation and growth process during deposition. The films were characterised by X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometer (ICP-OES), field emission scanning electron microscope (FESEM), optical contact angle (OCA) and UV–visible transmission spectra (UV–vis). The qualitative and quantitative bactericidal efficiency was studied through SEM image of the treated E. coli cells (Escherichia coli NCIM 2809) and optical density (OD) measurement using UV–vis spectrometer, respectively. The better bactericidal efficiency was observed in the film with more Al content. The crystallinity, surface chemical composition, band gap in context of Al present in the films were discussed and correlated to bactericidal efficiency in the light of in situ investigation of plasma from OES.

Synthesis of titanium oxide thin films containing antibacterial silver nanoparticles by a reactive magnetron co-sputtering system for application in biomedical implants

Titanium oxide thin films containing silver (Ag) nanoparticles were synthesized on commercially pure titanium (cp-Ti) substrates using a reactive magnetron co-sputtering method. The goal was to maximize bactericidal activity along with sustained biocompatibility. Furthermore, this study examined the correlation between Ag nanoparticle dispersion in the films and the antibacterial efficacy of the Ag ions released from the films. The results showed that there might be two factors affecting the inhibition of bacterial attachment to the surface of the specimens: surface morphology and Ag ion release. MTT assay results demonstrated that there was no cytotoxicity on fibroblast cells in any group. Overall, the magnetron sputtered Ag nanoparticle-containing titanium oxide coatings in this study can be used as an efficient antibacterial layer with sustained biocompatibility.

Middle-ultraviolet-enhanced photodetectors based on Mg0.4Zn0.6O/ZnO homojunction with a high selectivity for 300 nm around light

High-quality Mg0.4Zn0.6O film with a ZnO buffer layer was prepared on glass by the reactive magnetron cosputtering method, and the MgZnO/ZnO homojunctions were fabricated into metal–semiconductor–metal middle ultraviolet (UV) photodetectors (PDs). The MgZnO-based PD with a ZnO buffer layer showed a high selectivity for 300 nm around middle UV light and its responsivity was larger than that of the PD without a buffer layer. Its peak responsivity was 0.45 A W−1 at 300 nm under −5 V bias, which was comparable to the highest value ever reported in MgZnO-based PDs. Also, we observed that the PDs with a smaller spacing of the finger electrodes showed a larger responsivity, indicating that the PD with a small spacing shows a large internal gain. The results may provide a simple route to gain low-cost and high-performance middle UV PDs.

Effect of annealing on microstructure and dielectric properties of Zn2Ti3O8 thin films by reactive co-sputtering

Microstructure and dielectric properties of Zn2Ti3O8 films deposited on Pt/Cr/SiO2/Si via a DC reactive magnetron co-sputtering method using zinc and titanium metal targets in O2/Ar atmosphere are investigated. The as-deposited Zn–Ti–O film has an amorphous microstructure. A single Zn2Ti3O8 phase appeared when the films were annealed at 500°C and 600°C for 1h. As the temperature further increased to 700 and 800°C, it was found that Zn2Ti3O8 and ZnTiO3 phases coexisted. A phase transformation from cubic Zn2Ti3O8 and rhombohedral ZnTiO3 to cubic Zn2TiO4 and rutile TiO2 was observed while a further increase in temperature up to 900°C. The heat treatment also induces a change in the surface morphology of the thin films observed by scanning electron microscopy. Transmission electron microscopy examination indicated that the film annealed at 700°C was composed of Zn2Ti3O8 and ZnTiO3 with fine and large grains in microstructure, respectively. The study also reveals that the dielectric constant of the films depends on the annealing temperature. When annealing at 600°C, the Zn2Ti3O8 films has the following properties at 1MHz: dielectric constant=32.9, tan δ=0.022.

MgZnO-based metal-semiconductor-metal solar-blind photodetectors on ZnO substrates

Using lattice matched ZnO substrates, wurtzite single crystalline Mg0.49Zn0.51O films were obtained by reactive magnetron cosputtering method, and the heterostructures of MgZnO/ZnO were fabricated into metal-semiconductor-metal solar-blind photodetectors (SBPDs). Calculated and experimental results demonstrate that the response of the ZnO substrate can be suppressed by adopting a thick MgZnO epilayer. The SBPD with a 2 μm thick MgZnO epilayer shows a peak responsivity of 304 mA/W at 260 nm under 10 V bias, which is comparable to the highest value ever reported in MgZnO-based SBPDs. A rejection ratio (R260 nm/R365 nm) over 5×102 is also observed, indicating fully suppression of the signal from ZnO substrate.

Enhancing The Optical And Electrical Properties of Si-based Nanostructured Materials

Multilayer structures of Si rich silicon oxide (SiOx) alternated with two types of dielectric sublayers viz. SiO2 or SiNx have been studied. An enhancement in the density of nanoclusters within the SiOx sublayer is achieved by using the reactive magnetron co-sputtering method. The effect of SiNx sublayer thickness on the photoluminescence properties is investigated. We succeed in enhancing the absorption and the pholuminescence properties of the multilayers by replacing SiO2 by SiNx sublayers. We also achieve a higher conductivity in SiOx/SiNx with an improved thermal budget. This preliminary study gives a deep insight to optimize materials for future solar cell device applications with enhanced properties at reduced thermal budget.

Photoenhanced Degradation of Methylene Blue on Cosputtered M:TiO2 (M = Au, Ag, Cu) Nanocomposite Systems: A Comparative Study

Titania thin film system containing noble metallic nanoparticles such as Au, Ag, and Cu have been prepared by utilizing radio frequency reactive magnetron cosputtering method. The structural and morphological properties of the thin films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). Surface chemical composition of the films was determined by X-ray photoelectron spectroscopy (XPS). Optical properties of the TiO2 annealed films containing Au, Ag, and Cu metallic nanoparticles were investigated by UV−visible spectrophotometry showing surface plasmon resonance of the metals. The photocatalytic activity of all synthesized samples annealed at 600 °C in an Ar + H2(80 + 20%) environment was evaluated by measuring the rate of photodegradation reaction of methylene blue (MB) under similar conditions in the presence of UV and visible light irradiation. The Au:TiO2 and Cu:TiO2 thin film systems significantly enhanced photodecomposition of MB resulting in 80 and 90% of its initial concentration after 200 min photoirradiation, respectively. The increase in the surface roughness measured by AFM observation and the presence of the Ti3+ oxygen vacancy in the photoirradiated thin films were found responsible for the enhancement of the MB photodegradation reaction. The photoenhancement of the studied was determined in the following order: Cu:TiO2 > Au:TiO2 > Ag:TiO2 > TiO2.

Mechanical, tribological, and electrochemical behavior of Cr1−xAlxN coatings deposited by r.f. reactive magnetron co-sputtering method

Abstract Chromium aluminum nitride (Cr 1− x Al x N) coatings were deposited onto AISI H13 steel and silicon substrates by r.f. reactive magnetron co-sputtering in (Ar/N 2 ) gas mixture from chromium and aluminum targets. Properties of deposited Cr 1− x Al x N coatings such as compositional, structural, morphological, electrochemical, mechanical and tribological, were investigated as functions of aluminum content. X-ray diffraction patterns of Cr 1− x Al x N coatings with different atomic concentrations of aluminum (0.51 x 1− x Al x N cubic and w-AlN phases, respectively. The rate of corrosion of the steel coated with Cr 1− x Al x N varied with the applied power; however, always being clearly lower when compared to the uncoated substrate. The behavior of the protective effect of the Cr 1− x Al x N coatings is based on the substitution of Cr for Al, when the power applied to the aluminum target increases. The mechanical properties were also sensitive to the power applied, leading to a maximum in hardness and a reduced elastic modulus of 30 and 303 GPa at 350 W and a monotonic decrease to 11 and 212 GPa at 450 W, respectively. Finally, the friction coefficient measured by pin-on disk revealed values between 0.45 and 0.70 in humid atmosphere.